Coating of wood is generally clear coating which is finished by directly expressing the quality and grain of the wood, and the main part of this coating art comprises the coating of furnitures. However, the coating of woods unlike that of metal materials has a disadvantage that such coating cannot be treated regularly due to the type of woods. That is, the properties of woods are distinguished from each other depending on the kinds of trees, the grains of the surface will vary depending on the sawings of woods, the stretching properties will vary depending on the directions of grains, and the tissues of the woods are uneven and thus result in different absorption of a coating.
On the other hand, the clear coating of woods had been started with oily varnish and lac varnish, and then a variety of synthetic coatings and coating methods have been developed by way of cashew coatings as an alternative of glue. Furthermore, the coloring methods with chemical agents have been practiced, but such coatings in the prior art often employ organic solvents, thus resulting in the inconvenience for their handling as well as environmental pollution. In addition, such coatings have also a problem that the coatings are malodorous not only during coating but also after coating, and that such coatings are hardly coated uniformly.